Interestingly the author of the original novel, Robert Bloch, wrote two sequels that were completely unrelated to the sequel movies.

So there's an enormous amount of Psycho-related material out there, pretty much none of which (IMO) is anywhere near the quality of the original Hitchcock film.

IIRC Hitchcock intended Psycho as a quick, low-budget B film to satisfy the studio after the disappointing performance of Vertigo, which he considered his artistic masterpiece. And Psycho turned out to be the movie he is best known for, and in many ways influenced modern cinema more than any of his other works.

__________________"Do not fear mistakes. There are none." - Miles Davis